Lower Shabelle governor Abdulkadir Mohamed Nor Sidii said the militants attacked the four villages of Awdheegle, Mubaarak, Dameeri and Shaam on Friday night.
"They attacked the villages last night and heavy fighting broke out. Unfortunately, we lost a senior military commander in the fight," Sidii said.
Local resident Mahamud Nor told Xinhua the fighting broke out at 2:00 a.m. and has been going on into the morning.
"We heard heavy gunfire while we were sleeping, and soon there was continuous fighting. We cannot get out of our houses because the fighting is still going on," another resident told Xinhua by phone.
Al-Shabaab still commands control of some parts of the Lower Shabelle region though they have been pushed from major towns by a joint Somali National Army and African Union backed force AMISOM operations.